That means that there is a very high chance something Donkey Kong Universe related is in the works.
My opinion is that it is most likely a Diddy Kong Racing title.
Why Diddy Kong Racing?
1. Retro Studios, although a long time ago now, was given experience in developing remixed tracks for Mario Kart 7 for design training purposes. This indicates that Nintendo had it in their minds that they would develop within that genre. Nintendo's closest IP to that is Diddy Kong Racing.
2. Diddy Kong Racing was popular on N64 - at the time of its release, it was one of the fastest selling games in history.
3. The Mario Kart-style genre is A LOT bigger now than it was on the N64. Look at the sales of Mario Kart DS (23M), Mario Kart Wii (36M), Mario Kart 7 (14.3M) and Mario Kart 8 (12M+ and growing).
4. There is a noticeable gap in Nintendo's lineup when it comes to racing games and the existing demand for them on Nintendo consoles; especially Mario Kart style games. Mario Kart 8 was a launch window game, but fitting another one in for later 2018 to early 2020 would be mint! (sorry, I had to! I haven't used that millennial buzzword before)!
5. David Wise is working in Austin Texas, where Retro Studios is located.
Why not another DKC title? They are most experienced in that.
Answer: I think it could be that too, but less probable.
1. No need to fill a 2D platformer gap. 2D platformers have seen an incredible resurgence in recent times. The primary platform for these is the Switch, there are TONS of them coming out, and people are gravitating toward them. Putting a DKC title on there won't be filling any gaps. Nintendo themselves already has two other new 2D platformers coming out with Kirby and Yoshi.
2. We are getting a somewhat new DKC game in 2018. While some players have already played DKC TF, the original sold to very few of the potential fans. The release will be an original title to the majority of Switch owners. Looking at DKCR, it's clear that most potential DKC fans didn't buy the Wii U for TF; sales profoundly declined in sales from DKCR (It sold only 26%).
Don't get me wrong, I think Nintendo is considering a new DKC game for the future, my doubts are that it is due for release this year or anytime soon.
Under the assumption that Diddy Kong Racing is a reality, I would guess there is a concept and prototype for a new DKC game is already in existence.
There's potential that part of the reason for the port of TF is a bit of a business case test before Nintendo greenlights another DKC.
If DKC: TF sales projections hit certain goals - then Nintendo will hammer that green light!
Alternatively, if the game doesn't hit targets, the concept/prototype will be put on the shelf until next generation.
My estimate is that the green light number is probably 2M units this year.
David Wise working for Nintendo link: http://nintendoeverything.com/rumor-david-wise-working-on-something-at-retro-studios/
I describe myself as a little dose of toxic masculinity.